Printing press control system (xink)

ABSTRACT

A system for controlling the operation of a printing press used to apply an aqueous printable electrically conductive ink onto a substrate to create electrically conductive traces of such ink includes a probe for contacting the electrical traces and for obtaining a resistance measurement therefrom. A computer receives the resistance measurement, compares such measurement with pre-selected data correlating resistance with acceptable performance criteria for such traces, determines whether such resistance measurement signifies acceptable performance, and signals an appropriate mechanism for identifying those electrical traces which do not meet the acceptable performance criteria. Unacceptable traces are removed from the press prior to further processing. The computer can also signal an ink replenishment or conditioning system, contained in a replaceable cartridge, to correct any abnormalities in the ink properties.

The present invention relates to the control of a printing pressoperating to print electrical conductors formed of an aqueous printabledispersion on a substrate.

BACKGROUND OF THE INVENTION

Commonly owned Canadian Patent Applications No. 2,509,608 of Jun. 9,2005 and 2,528,420 of Nov. 30, 2006 describe an aqueous printableelectrical conductor that can be printed on a substrate for use as RFIDantennas and for other purposes. The conductor forms an electrical traceusable for such antennas, for printed medical, chemical and biologicalsensors, for printed touchpads, and for other related devices. Wheresuch printed conductors are attached to CPUs (chips) as in the case ofRFID tags, it is desirable for reasons of economy to know if theelectrical characteristics of the printed conductor are within anacceptable range before a chip is attached. Since the chip is typicallyattached in-line with the high-speed printing process, the evaluation ofthe printed conductor and feedback must be rapid.

SUMMARY OF THE INVENTION

The present invention is designed to evaluate the electricalcharacteristics of printed conductors such as, but not limited to, RFIDantennas in-line during the printing process, to provide information asto whether the printed conductor is within an acceptable range ofelectrical characteristics, and to provide feedback to the systemallowing chip attachment to be aborted if the conductor is not withinspecification. It is also designed to adjust the characteristics of theconductive ink being supplied to the printing press and other presscharacteristics in real time.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram illustrating schematically the processinvolved with the press control system of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1 the following explanation describes the use ofthe proposed invention in the high-speed printing of RFID antennas usingconductive inks as described in the above-identified patent applicationsand the subsequent attachment of a chip to the antenna to make acompleted RFID tag, all carried out on-line and in real time.

As the antennas come off the printer at high speed, the probes of theIn-line Resistance Measuring Tool (IRMT) 10 contact the antenna andmeasure the resistance across it. The probes are located at the press ina location where the ink has dried to a point that contact by the probeswill not damage the conductive trace. This location will likely varyfrom printing press to printing press, depending on the configurationthereof. The information obtained by the probes is fed to acomputer-based Ink Conditioning Controller (ICC) 12. The ICC 12 alsoreceives information about printing speed from the Press PLC 14. The ICC12 then compares the data from the press to a pre-programmed AntennaDesign File (ADF). The ADF contains information from the antennadesigner about the measuring points on the antenna, the number ofmeasurements per antenna and the range of measurement calculations thatsignify an acceptable antenna. The ICC 12 decides, on the basis of thiscomparison, whether an antenna is acceptable for chip attachment.Information on unacceptable antennas is sent to the Rejected AntennaMarker (RAM) 16 which marks, otherwise identifies, diverts or aborts therejected antenna from the print process. Acceptable traces or antennascan be suitably marked with, for example, resistance measurements, orserial or lot numbers for inventory and quality control.

In parallel with the above process, the ICC 12 also compares the antennaresistance data to pre-programmed data correlating resistance data withink quality, anilox roll surface, temperature, humidity, closed or openpress ink reservoir and type of dryer in use on the press. If the inkquality requires adjustment, this information is sent to the InkConditioning Pump (ICP) 18. The ICP 18 then pumps an appropriate amountof Ink Conditioning Agent from the IC Reservoir 20 to the Pre-mixReservoir 22, from which it is pumped to the press Ink CirculationSystem 24. The conditioner could alter different qualities orcharacteristics of the ink, a primary characteristic to be modifiedbeing the ink viscosity. The press Ink Circulation System 24 circulatesink through the Pre-mix Reservoir 22 to provide homogeneity of the inksupplies. This recirculation system maintains ink quality within designparameters as it flows through the press pipe lines and also takes intoconsideration abnormal ink usage, ensuring that a proper volume of inkis available for efficient operation of the press.

The data relating printed conductor resistance to press and press inkcharacteristics are stored in the ICC 12 where it can be selected at thebeginning of each print run. The settings for successful runs can thenbe stored in the ICC 12 for future runs using the same substrate, ink,environmental and press characteristics.

The Ink Conditioning Pump 18, Ink Conditioning Agent Reservoir 20 andPre-mix Reservoir 22 comprise a replaceable cartridge 30 that can beinserted into the press as required. The cartridge 30 is a separatenon-reusable item which permits the press operator to produce highquality printed ink traces without having to understand the complexchemistry of conductive inks. The operator only has to insert a newcartridge when the old cartridge has served its purpose. The componentsof the cartridge are all tuned by the ink manufacturer for optimumperformance of any particular press and printing operation.

1. A system for controlling the operation of a printing press used to apply an aqueous printable electrically conductive ink onto a substrate to create electrically conductive traces of such ink on such substrate, comprising: probe means for contacting said electrical traces and for obtaining a resistance measurement therefrom; computer means for receiving such resistance measurement, comparing such measurement with pre-selected data correlating resistance with acceptable predetermined performance criteria for such traces, determining whether such resistance measurement signifies acceptable performance, and signalling selection means for identifying those electrical traces which do not meet the acceptable performance criteria; and means associated with said press for rejecting substrate having unacceptable electrical traces thereon from the press prior to further processing.
 2. The system according to claim 1 wherein said electrical traces include RFID antennas, printed medical, chemical and biological sensors, printed touchpads and related devices.
 3. The system according to claim 1 or claim 2 wherein said probe means contact the electrical traces at a predetermined point along the printing line where said traces are sufficiently dry that they will not be damaged by contact with said probe means.
 4. The system according to any one of claims 1 to 3 wherein said rejecting means includes means for preventing the attachment of unacceptable electrical traces to a chip.
 5. The system according to any one of claims 1 to 4 including printing means for applying information including but not limited to serial numbers and resistance measurements to acceptable substrate during the printing process to facilitate subsequent inventory control and quality assurance processes.
 6. The system according to any one of claims 1 to 5 wherein said computer means is capable of signalling an ink replenishment system for correcting deficiencies in ink quality in real time during operation of said press following the correlation of said resistance measurement with said pre-selected data.
 7. The system according to claim 6 wherein said ink replenishment system comprises an ink conditioning pump which receives control signals from said computer means, an ink conditioning agent reservoir connected to said pump and containing an ink conditioning agent, and an ink reservoir connected to an ink circulation system of said press, said pump feeding a controlled volume of conditioning agent to said ink reservoir so that ink flowing from said ink reservoir will exhibit acceptable performance criteria.
 8. The system according to claim 7 wherein said ink conditioning agent is capable of altering the viscosity of the ink flowing from said ink reservoir to said press.
 9. The system according to any one of claims 1 to 8 wherein said computer means is capable of correlating said resistance measurements with the operating conditions of the press and with the viscosity of the ink.
 10. The system according to any one of claims 6 to 9 wherein the components of said ink replenishment system may be all contained within a replaceable cartridge that can be removably connected to said press.
 11. A replenishment system for use with a printing press used to apply an aqueous printable conductive ink onto a substrate to create electrically conductive traces of such ink on the substrate, comprising: an ink conditioning pump which receives control signals from a computer means; an ink conditioning agent reservoir connected to said pump and containing an ink conditioning agent; and an ink reservoir connected to an ink circulation system of said press, said pump being adapted to feed a controlled volume of said conditioning agent to said ink reservoir so that ink flowing from said ink reservoir will exhibit acceptable performance criteria as determined by said computer means.
 12. The system of claim 11 wherein said ink conditioning agent is capable of altering the viscosity of the ink flowing from said ink reservoir to said press.
 13. The system of claim 11 or claim 12 wherein said ink conditioning pump, said ink conditioning agent reservoir and said ink reservoir are contained within a replaceable cartridge that can be removably connected to said press.
 14. A system for controlling the operation of a printing press used to apply an aqueous printable electrically conductive ink onto a substrate to create electrically conductive traces of such ink on such substrate, comprising: probe means for contacting said electrical traces and for obtaining a resistance measurement therefrom; an ink replenishment system containing an ink conditioning agent capable of correcting deficiencies in ink quality; and computer means for receiving such resistance measurement, comparing such measurement with pre-selected data correlating resistance with predetermined acceptable performance criteria for such traces, determining whether such resistance measurement signifies a deficiency from such acceptable performance, and signalling said ink replenishment system to apply an appropriate amount of said ink conditioning agent to an ink circulation system of said press in order to correct such deficiency.
 15. The system of claim 14 further comprising selection means for identifying those electrical traces which do not meet the acceptable performance criteria, and means for rejecting substrate having unacceptable electrical traces thereon form the press prior to further processing.
 16. The system according to claim 14 or claim 15 wherein said probe means contact the electrical traces at a predetermined point along the printing line where said traces are sufficiently dry that they will not be damaged by contact with said probe means.
 17. The system according to claim 15 wherein said rejecting means includes means for preventing the attachment of unacceptable electrical traces to a chip.
 18. The system according to any one of claims 14 to 17 including printing means for applying information including but not limited to serial numbers and resistance measurements to acceptable substrate during the printing process to facilitate subsequent inventory control and quality assurance processes.
 19. The system according to any one of claims 14 to 18 wherein said ink replenishment system comprises an ink conditioning pump which receives control signals from said computer means, an ink conditioning agent reservoir connected to said pump and containing said ink conditioning agent, and an ink reservoir connected to said ink circulation system of said press, said pump feeding a controlled volume of said ink conditioning agent to said ink reservoir so that ink flowing from said ink reservoir will exhibit acceptable performance criteria.
 20. The system according to claim 19 wherein said ink conditioning agent is capable of altering the viscosity of the ink flowing from said ink reservoir to said press.
 21. The system according to claim 20 wherein said computer means is capable of correlating said resistance measurements with the operating conditions of the press and the viscosity of the ink.
 22. The system according to any one of claims 19 to 21 wherein said ink conditioning pump, said ink conditioning agent reservoir, and said ink reservoir are contained within a replaceable cartridge that can be removably connected to said press.
 23. The system of claim 9 or claim 21 wherein said operating conditions include but are not limited to one or more of the operating temperature of the press, the humidity in the vicinity of the press, the anilox roil surface, the ink quality, and the type of dryer on the press. 